纯主应力轴旋转条件下粉细砂的变形特性研究

Deformation behavior of fine sands under pure principal stress rotation

采用空心圆柱扭剪仪对汶河粉细砂进行了一系列不同中主应力系数和初始剪应力的纯主应力轴旋转试验,研究了主应力轴沿同一方向纯旋转条件下粉细砂的变形特性。研究表明,主应力轴的旋转会使粉细砂产生一定的塑性变形,且变形的发展受中主应力系数和初始剪应力的影响;纯主应力轴旋转条件下砂土的非共轴变形特性较为明显,且非共轴角的峰值点出现在大主应力方向角为0°和90°的两个位置处;同时,中主应力系数对非共轴角的变化有着较为明显的影响,非共轴角会随中主应力系数的增大而减小。

A series of tests for Wenhe fine sands with different intermediate principal stress parameter and initial shear stress subjected to pure principal stress rotation are conducted using Hollow Cylinder Apparatus( HCA). Based on the experimental results,the deformation behaviour especially the non-coaxiality of fine sands under pure principal stress rotation is studied. It is found that the fine sands would produce obvious plastic deformation under pure principal stress rotation,and the deformation behaviour is greatly influenced by intermediate principal stress parameter and initial shear stress. It is also indicated that during the pure principal stress rotation tests,the non-coaxial behavior can be observed obviously,and the peak value of non-coaxial angle would appear at two locations where the principal stress direction angle is 0 ° and 90 °. Meanwhile,the non-coaxial angle is also greatly influenced by intermediate principal stress parameter and would decrease with the increase of intermediate principal stress parameter.